Aqueous potassium-ion batteries(APIBs),recognized as safe and reliable new energy devices,are considered as one of the alternatives to traditional batteries.Layered MnO_(2),serving as the main cathode,exhibits a lower...Aqueous potassium-ion batteries(APIBs),recognized as safe and reliable new energy devices,are considered as one of the alternatives to traditional batteries.Layered MnO_(2),serving as the main cathode,exhibits a lower specific capacity in aqueous electrolytes compared to organic systems and operates through a different reaction mechanism.The application of highly conductive graphene may effectively enhance the capacity of APIBs but could complicate the potassium storage environment.In this study,a MnO_(2) cathode pre-intercalated with K~+ions and grown on graphene(KMO@rGO) was developed using the microwave hydrothermal method for APIBs.KMO@rGO achieved a specific capacity of 90 mA h g^(-1) at a current density of 0.1 A g^(-1),maintaining a capacity retention rate of>90% after 5000 cycles at 5 A g^(-1).In-situ and exsitu characterization techniques revealed the energy-storage mechanism of KMO@rGO:layered MnO_(2)traps a large amount of "dead" water molecules during K~+ions removal.However,the introduction of graphene enables these water molecules to escape during K~+ ions insertion at the cathode.The galvanostatic intermittent titration technique and density functional theory confirmed that KMO@rGO has a higher K~+ions migration rate than MnO_(2).Therefore,the capacity of this cathode depends on the interaction between dead water and K~+ions during the energy-storage reaction.The optimal structural alignment between layered MnO_(2) and graphene allows electrons to easily flow into the external circuit.Rapid charge compensation forces numerous low-solvent K~+ions to displace interlayer dead water,enhancing the capacity.This unique reaction mechanism is unprecedented in other aqueous battery studies.展开更多
Nanoscale bimetallic Ni/Fe particles were synthesized from the reaction of sodium borohydride (NaBH4) with reduction of Ni^2+ and Fe^2+ in aqueous solution. The obtained Ni/Fe particles were characterized by TEM ...Nanoscale bimetallic Ni/Fe particles were synthesized from the reaction of sodium borohydride (NaBH4) with reduction of Ni^2+ and Fe^2+ in aqueous solution. The obtained Ni/Fe particles were characterized by TEM (transmission electron microscope), XRD (X-ray diffractometer), and N2-BET. The dechlorination activity of the Ni/Fe was investigated using p-chlorophenol (p-CP) as a probe agent. Results demonstrated that the nanoscale Ni/Fe could effectively dechlorinate p-CP at relatively low metal to solution ratio of 0.4 g/L (Ni 5 wt%). The target with initial concentration ofp-CP 0.625 mmol/L was dechlorinted completely in 60 rain under ambient temperature and pressure. Factors affecting dechlorination efficiency, including reaction temperature, pH, Ni loading percentage over Fe, and metal to solution ratio, were investigated. The possible mechanism of dechlorination ofp-CP was proposed and discussed. The pseudo-first- order reaction took place on the surface of the Ni/Fe bimetallic particles, and the activation energy of the dechlorination reaction was determined to be 21.2 kJ/mol at the temperature rang of 287-313 K.展开更多
TiO2 and montmorillonite composite photocatalysts were prepared and applied in degrading γ-hexachlorocyclohexane (γ-HCH) in soils. After being spiked with γ-HCH, soil samples loaded with the composite photocataly...TiO2 and montmorillonite composite photocatalysts were prepared and applied in degrading γ-hexachlorocyclohexane (γ-HCH) in soils. After being spiked with γ-HCH, soil samples loaded with the composite photocatalysts were exposed to UV-light irradiation. The results indicated that the photocatalytic activities of the composite photocatalysts varied with the content of TiO2 in the order of 10%〈70%〈50% 〈30%, Moreover, the photocatalytic activity of the composite photocatalysts with TiO2 content 30% was higher than that of the pure P25 with the same mass of TiO2. The strong adsorption capacity of the composite photocatalysts and quantum size effect may contribute to its increased photocatalytic activities. In addition, effect of dosage of composite photocatalysts and soil pH on γ-HCH photodegradation was investigated. Pentachlorocyclohexene, trichlorocyclohexene, and dichlorobenzene were detected as photodegradation intermediates, which were gradually degraded with the photodegradation evolution.展开更多
The solubility and sorption of oil by uncontaminated clay loam and silt loam soils were studied from water and cosolvent/water solutions using batch techniques. The data obtained from the dissolution and sorption expe...The solubility and sorption of oil by uncontaminated clay loam and silt loam soils were studied from water and cosolvent/water solutions using batch techniques. The data obtained from the dissolution and sorption experiments were used to evaluate the applicability of the cosolvent theory to oil as a complex mixture. Aqueous solubility and soil-water distribution coeffcients (Kd,w, L/kg) were estimated by extrapolating from cosolvent data, with a log-linear cosolvency model, to the volume fraction of cosolve...展开更多
Effects of natural organic matters(NOM) and hydrated metal oxides(HMO) in sediments on the anaerobic degradation of γ 666, p,p' DDT and HCB were investigated by means of removing NOM and HMO in Liaohe R...Effects of natural organic matters(NOM) and hydrated metal oxides(HMO) in sediments on the anaerobic degradation of γ 666, p,p' DDT and HCB were investigated by means of removing NOM and HMO in Liaohe River sediments sequentially. The results showed that the anaerobic degradation of γ 666, p,p' DDT and HCB followed pseudo first order kinetics in different sediments. But, the extents and rates of degradation were different, even the other conditions remained the same. Anaerobic degradation rates of γ 666, p,p' DDT and HCB were 0 020 d -1 , 0 009 d -1 and 0 035 month -1 respectively for the sediments without additional carbon resources. However, with addition of carbon resources, the anaerobic degradation rates of γ 666, p, p ' DDT and HCB were 0 071 d -1 , 0 054 d -1 and 0 088 month -1 in the original sediments respectively. After removing NOM, the rates were decreased to 0 047 d -1 , 0 037 d -1 and 0 066 month -1 ; in the sediments removed NOM and HMO, the rates were increased to 0 067 d -1 , 0 059 d -1 and 0 086 month -1 . These results indicated that NOM in the sediments accelerated the anaerobic degradation of γ 666, p,p' DDT and HCB; the HMO inhibited the anaerobic degradation of γ 666, p,p' DDT and HCB.展开更多
A chemical sequential separation procedure for sediment has been developed for the adsorptive investigation of hydrophobic organic compounds(HOCs) including four fractions: carbonate, hydrous metallic oxide(ferric oxi...A chemical sequential separation procedure for sediment has been developed for the adsorptive investigation of hydrophobic organic compounds(HOCs) including four fractions: carbonate, hydrous metallic oxide(ferric oxide, manganese oxide and alumina), clay and organic matter. Adsorption isotherms of these hydrophobic solute probes, such as hexachloroethane, lindane and 1,2,4,5 tetrachlorobenzene were measured for model sorbents, model and natural sediment, and the latter of which was pretreated with the simplified sequential separation method. The linear and Langmuir models are applied to correlate the experimental data of humic substance and other model sorbents respectively. Multi component Adsorptive Model (MCAM) was used to simulate adsorption isotherms of model and natural sediment. The results reveal that(1) the separation efficiencies of carbonate, organic matter, ferric oxide, manganese oxide and alumina are 98.1%, 72.5%, 82.6%, 93.5% and 83.3%, respectively; (2) except for removing metallic oxide, the external structure of sediment is not changed greatly after separation; (3) the MCAM correlates the data of adsorption isotherm rather well with the maximal relative deviations of 9.76%, 6.78% and 9.53% for hexachloroethane, lindane and 1,2,4,5 tetrachlorobenaze in model sediment, respectively. The MCAM can clearly give expression to the different adsorptive mechanisms for HOCs in organic and inorganic matter, though the experimental data in each component are not very accurate due to the sequential separation efficiency.展开更多
Hyperbranched polymer composed of G1 polyamidoamine (PAMAM) and branched with poly (propylene oxide) (PPO)-block-poly (ethylene oxide) (PEO) was investigated to interact with sodium dodecyl sulfate (SDS) and di-dodecy...Hyperbranched polymer composed of G1 polyamidoamine (PAMAM) and branched with poly (propylene oxide) (PPO)-block-poly (ethylene oxide) (PEO) was investigated to interact with sodium dodecyl sulfate (SDS) and di-dodecyl dimethyl ammonium bromide (DDAB), respectively, by the methods of turbidity titration and analysis, rheology measurements, dynamic light scattering (DLS) and transmission electron microscopy (TEM). It was noticeable that even at extremely low concentration of SDS (even far from the critical micelle concentration (cmc)), the system exhibits high turbidity, indicating that SDS molecules can insert into cationic amine groups and hydrophobic microenvironment, resulting in the formation of polymer-SDS complexes with large size. At the SDS concentration range of below 0.1 mM, the turbidity and cloud point (CP) temperature of the system keep almost invariable, mostly because of the repulsion between SDS molecules and the complexes. And, therefore, the size of the mixed aggregates retains almost constant. In the case of vesicle system of DDAB, the aggregates are in the size of 100 nm - 200 nm and 500 nm - 3000 nm at the concentrations of 30 mM and 100 mM, respectively. However, in the mixture of hyperbranched polymer with DDAB, by comparison, the size is smaller in a binary system than that of in DDAB system. So it is reasonable to infer that DDAB molecules remove from multilamellar vesicles of DDAB to the hydrophobic microenvironment of hyperbranched polymer aggregates, with the addition of the hyperbranched polymer. It leads to the destruction of the gel-like conformation in DDAB system, leading to the shear thinning of the mixture and, as a result, the viscoelastic character of the system is lost in a large degree.展开更多
We have discussed the materials of solar cell based on hybrid organic–inorganic halide perovskites with formamidinium(NH_2CH = NH_2^+or FA) lead iodide. Firstly, we build the structure of formamidinium lead iodide(FA...We have discussed the materials of solar cell based on hybrid organic–inorganic halide perovskites with formamidinium(NH_2CH = NH_2^+or FA) lead iodide. Firstly, we build the structure of formamidinium lead iodide(FAPbI_3) by using the material studio. By using the first-principles calculations, the energy band structure, density of states(DOS), and partial DOS(PDOS) of the hydrazine-iodide lead halide are obtained. Then, we theoretically analyze a design scheme for perovskite solar cell materials, published in [Science 354, 861(2016)], with the photoelectric conversion efficiency that can reach 20.3%. Also, we use non-toxic elements to replace lead in FAPbI_3 without affecting its photoelectric conversion efficiency. Here in this work, we explore the energy band structure, lattice constant, light absorption efficiency, etc. After the Ca, Zn, Ge Sr, Sn, and Ta atoms replacing lead(Pb) and through comparing the spectral distributions of the solar spectrum, it can be found that FAGeI_3, FASnI_3, and FAZnI_3 have better absorbance characteristics in the solar spectrum range. If the band gap structure is taken into account, FAGeI_3 will become an ideal material to replace FAPbI_3, although its performance is slightly lower than that of FAPbI_3. The toxicity of Pb is taken into account, and the Ge element can be used as a substitute element for Pb. Furthermore, we explore one of the perovskite materials, i.e., FA0.75Cs_(0.25)Sn_(0.25)Ge_(0.75)I_3 whose photovoltaic properties are close to those of FA_(0.75)Cs_(0.25)Sn_(0.5)Pb_(0.5)I_3, but the former does not contain toxic atoms.Our results pave the way for further investigating the applications of these materials in relevant technologies.展开更多
Organic matter and iron and maganese oxides have been considered as the major affecting factors for metals in anoxic or oxidized sediment. In recent research, clay and sulfide are found as major factors in oxic or oxi...Organic matter and iron and maganese oxides have been considered as the major affecting factors for metals in anoxic or oxidized sediment. In recent research, clay and sulfide are found as major factors in oxic or oxidized sediments that might affect bioavailability of metals. To test this hypothesis, the influence of sulfide, measured as acid-volatile sulfide (AVS), and clay content on the bioavailability of zinc and cadmium in sediments was examined. Laboratory simulative experiment and field verification experiment were conducted, showing that the bioavailability of zinc and cadmium is strongly correlated to AVS and clay content in sediments. Taking into account both AVS and clay parameters in sediments together can better indicate the bioavailability of zinc and cadmium rather than considering one of them alone.展开更多
Two-phaseγ-TiAl/α_(2)-Ti_(3)Al lamellar intermetallics have attracted considerable attention because of their excellent strength and plasticity.However,the exact deformation mechanisms remain to be investigated.In t...Two-phaseγ-TiAl/α_(2)-Ti_(3)Al lamellar intermetallics have attracted considerable attention because of their excellent strength and plasticity.However,the exact deformation mechanisms remain to be investigated.In this paper,a solidified lamellar Ti-Al alloy with lamellar orientation at 0°,17°,and 73°with respect to the loading direction was stretched by utilizing molecular dynamics(MD)simulations.The results show that the mechanical properties of the sample are considerably influenced by solidified defects and tensile directions.The structure deformation and fracture were primarily attributed to an intrinsic stacking fault(ISF)accompanied by the nucleated Shockley dislocation,and the adjacent extrinsic stacking fault(ESF)and ISF formed by solidification tend to form large HCP structures during the tensile process loading at 73°.Moreover,cleavage cracking easily occurs on theγ/α_(2)interface under tensile deformation.The fracture loading mechanism at 17°is grain boundary slide whereas,at 73°and 0°,the dislocation piles up to form a dislocation junction.展开更多
An analytical solution in physical variable space is presented for transient gas flows during constant-rate production from a vertically-fractured well in an infinite homogeneous reservoir with finite fracture conduct...An analytical solution in physical variable space is presented for transient gas flows during constant-rate production from a vertically-fractured well in an infinite homogeneous reservoir with finite fracture conductivity.The solution is based on the short-time asymptotic solution and a new approximate transient elliptical flow solution,which covers transient flows from the bilinear flow regime to the pseudo-radial flow regime.The solution covers the well-known asymptotic solutions in both short-and long-time limits of bilinear and pseudo-radial flows.The analytical model provides a practical and reliable engineering tool to evaluate the fractured reservoir properties,which can be programmed using a spreadsheet.展开更多
Objective:To compare the efficacy and mechanism of zoledronic acid and Tc-MDP in the treatment of osteoporosis.Methods:From July 2011 to November 2015,232 patients with primary osteoporosis were selected and treated i...Objective:To compare the efficacy and mechanism of zoledronic acid and Tc-MDP in the treatment of osteoporosis.Methods:From July 2011 to November 2015,232 patients with primary osteoporosis were selected and treated in The First Affiliated Hospital of Hainan Medical College were selected and were divided into the 116 patients in the Tc-MDP group and 116 patients in the zoledronic acid group accorded to the treatment ways.The zoledronic acid group were given zoledronic acid treatment,1 time in one year.The Tc-MDP group were given Tc-MDP treatment,and the treatment were treated for 10 days for 1 course,1 course for 3 months,and a total of 3 years of treatment were observed.The prognosis and the changes of bone mineral density and hematological parameters were recorded.Results:The total effective rates of the zoledronic acid group and Tc-MDP group were 99.1%and 90.0%,respectively,and the zoledronic acid group were significantly higher than the Tc-MDP group(P<0.05).The bone mineral density of lumbar vertebrae and hip after treatment were significantly higher than that of the two groups before treatment,and the zoledronic acid group were also significantly higher than the Tc-MDP group(P<0.05).The joint tenderness scores of the two groups were significantly lower than those before treatment,and the Tc-MDP group were also significantly lower than the zoledronic acid group(P<0.05).There were no significant differences in serum calcium and blood phosphorus levels compared between the two groups(P>0.05),and the erythroeyte sedimentation rate(ESR)levels were lower than before treatment(P<0.05),The ESR levels of the Tc-MDP group were also significantly lower than that of the zoledronic acid group(P<0.05).Conclusion:The zoledronic acid and the application of Tc-MDP in the treatment of osteoporosis can increase bone density,relieve joint tenderness symptoms,reduce ESR content,and will not affect patients'blood calcium and blood phosphorus levels.However,zoledronic acid increases bone density significantly are better than the Yunke,and Yunke relieves joint pain significantly are more than zoledronic acid.展开更多
Objective:To observe the bone metabolism before and after131I treatment in premanopause female hyperthyroidism patients with low bone mass patients of different age.Methods:A total of 78 premanopause female patients h...Objective:To observe the bone metabolism before and after131I treatment in premanopause female hyperthyroidism patients with low bone mass patients of different age.Methods:A total of 78 premanopause female patients hyperthyroidism with low bone mass were divided into two different age groups: premanopause female patients less than 35 years old in group A (n=38). Patients above 35 in group B (n = 40). 78 healthy adults of same age were enrolled as the control group. The bone mineral density (BMD) and bone turnover markers including type I procollagen N-terminal propeptide (PINP),β-C-terminal telopeptides of type 1 collagen (β-CTx) of two groups were measured before and 6 months and 12 months after 131I treatment to observe the bone metabolism and the restorablility of BMD.Results: After prolonged treatment with131I, PINP andβ-CTX of group A decreased and BMD increased gradually in a time-dependence way. And there was no significant difference when compared to the normal after 12 months. PINP andβ-CTX of group B decreased gradually, after 12 months, BMD of group B restored when compared to the level of before treatment but lower than group A.Conclusions: In young female hyperthyroidism patients with low bone mass (<35 years), BMD can be restored to normal levels as reversing of high bone turnover after131I treatment. Short-term clinical observation showed that high bone turnover was reduced partly in premanopause female patients (>35 years) treated only with131I , but still at a high level, BMD can not restored completely.展开更多
基金financially supported by the Scientific and Technological Plan Project of Guizhou Province (Grant No. [2021]060)the Industry and Education Combination Innovation Platform of Intelligent Manufacturing and the Graduate Joint Training Base at Guizhou University (Grant No. 2020-520000-83-01-324061)the Guizhou Engineering Research Center for smart services (Grant No. 2203-520102-04-04-298868)。
文摘Aqueous potassium-ion batteries(APIBs),recognized as safe and reliable new energy devices,are considered as one of the alternatives to traditional batteries.Layered MnO_(2),serving as the main cathode,exhibits a lower specific capacity in aqueous electrolytes compared to organic systems and operates through a different reaction mechanism.The application of highly conductive graphene may effectively enhance the capacity of APIBs but could complicate the potassium storage environment.In this study,a MnO_(2) cathode pre-intercalated with K~+ions and grown on graphene(KMO@rGO) was developed using the microwave hydrothermal method for APIBs.KMO@rGO achieved a specific capacity of 90 mA h g^(-1) at a current density of 0.1 A g^(-1),maintaining a capacity retention rate of>90% after 5000 cycles at 5 A g^(-1).In-situ and exsitu characterization techniques revealed the energy-storage mechanism of KMO@rGO:layered MnO_(2)traps a large amount of "dead" water molecules during K~+ions removal.However,the introduction of graphene enables these water molecules to escape during K~+ ions insertion at the cathode.The galvanostatic intermittent titration technique and density functional theory confirmed that KMO@rGO has a higher K~+ions migration rate than MnO_(2).Therefore,the capacity of this cathode depends on the interaction between dead water and K~+ions during the energy-storage reaction.The optimal structural alignment between layered MnO_(2) and graphene allows electrons to easily flow into the external circuit.Rapid charge compensation forces numerous low-solvent K~+ions to displace interlayer dead water,enhancing the capacity.This unique reaction mechanism is unprecedented in other aqueous battery studies.
基金financially supported by the National Natural Science Foundation of China(51872341,51572209)the Start-up Funds for High-Level Talents of Sun Yat-sen University(38000-31131105)+1 种基金the Fundamental Research Funds for the Central Universities(19lgzd29)the Science and Technology Program of Guangzhou(201707010095)~~
基金Project supported by the National Basic Research Program (973) of China(No. 2003CB415006)the National Natural Science Foundation of China (No. 20337020)
文摘Nanoscale bimetallic Ni/Fe particles were synthesized from the reaction of sodium borohydride (NaBH4) with reduction of Ni^2+ and Fe^2+ in aqueous solution. The obtained Ni/Fe particles were characterized by TEM (transmission electron microscope), XRD (X-ray diffractometer), and N2-BET. The dechlorination activity of the Ni/Fe was investigated using p-chlorophenol (p-CP) as a probe agent. Results demonstrated that the nanoscale Ni/Fe could effectively dechlorinate p-CP at relatively low metal to solution ratio of 0.4 g/L (Ni 5 wt%). The target with initial concentration ofp-CP 0.625 mmol/L was dechlorinted completely in 60 rain under ambient temperature and pressure. Factors affecting dechlorination efficiency, including reaction temperature, pH, Ni loading percentage over Fe, and metal to solution ratio, were investigated. The possible mechanism of dechlorination ofp-CP was proposed and discussed. The pseudo-first- order reaction took place on the surface of the Ni/Fe bimetallic particles, and the activation energy of the dechlorination reaction was determined to be 21.2 kJ/mol at the temperature rang of 287-313 K.
基金Project supported by the National Natural Science Foundation of China(No. 29977003, 20507011)the State Ministry of Education of China(No. 00028)
文摘TiO2 and montmorillonite composite photocatalysts were prepared and applied in degrading γ-hexachlorocyclohexane (γ-HCH) in soils. After being spiked with γ-HCH, soil samples loaded with the composite photocatalysts were exposed to UV-light irradiation. The results indicated that the photocatalytic activities of the composite photocatalysts varied with the content of TiO2 in the order of 10%〈70%〈50% 〈30%, Moreover, the photocatalytic activity of the composite photocatalysts with TiO2 content 30% was higher than that of the pure P25 with the same mass of TiO2. The strong adsorption capacity of the composite photocatalysts and quantum size effect may contribute to its increased photocatalytic activities. In addition, effect of dosage of composite photocatalysts and soil pH on γ-HCH photodegradation was investigated. Pentachlorocyclohexene, trichlorocyclohexene, and dichlorobenzene were detected as photodegradation intermediates, which were gradually degraded with the photodegradation evolution.
基金the National Basic Research Program of China (No. 2004CB418504)
文摘The solubility and sorption of oil by uncontaminated clay loam and silt loam soils were studied from water and cosolvent/water solutions using batch techniques. The data obtained from the dissolution and sorption experiments were used to evaluate the applicability of the cosolvent theory to oil as a complex mixture. Aqueous solubility and soil-water distribution coeffcients (Kd,w, L/kg) were estimated by extrapolating from cosolvent data, with a log-linear cosolvency model, to the volume fraction of cosolve...
文摘Effects of natural organic matters(NOM) and hydrated metal oxides(HMO) in sediments on the anaerobic degradation of γ 666, p,p' DDT and HCB were investigated by means of removing NOM and HMO in Liaohe River sediments sequentially. The results showed that the anaerobic degradation of γ 666, p,p' DDT and HCB followed pseudo first order kinetics in different sediments. But, the extents and rates of degradation were different, even the other conditions remained the same. Anaerobic degradation rates of γ 666, p,p' DDT and HCB were 0 020 d -1 , 0 009 d -1 and 0 035 month -1 respectively for the sediments without additional carbon resources. However, with addition of carbon resources, the anaerobic degradation rates of γ 666, p, p ' DDT and HCB were 0 071 d -1 , 0 054 d -1 and 0 088 month -1 in the original sediments respectively. After removing NOM, the rates were decreased to 0 047 d -1 , 0 037 d -1 and 0 066 month -1 ; in the sediments removed NOM and HMO, the rates were increased to 0 067 d -1 , 0 059 d -1 and 0 086 month -1 . These results indicated that NOM in the sediments accelerated the anaerobic degradation of γ 666, p,p' DDT and HCB; the HMO inhibited the anaerobic degradation of γ 666, p,p' DDT and HCB.
文摘A chemical sequential separation procedure for sediment has been developed for the adsorptive investigation of hydrophobic organic compounds(HOCs) including four fractions: carbonate, hydrous metallic oxide(ferric oxide, manganese oxide and alumina), clay and organic matter. Adsorption isotherms of these hydrophobic solute probes, such as hexachloroethane, lindane and 1,2,4,5 tetrachlorobenzene were measured for model sorbents, model and natural sediment, and the latter of which was pretreated with the simplified sequential separation method. The linear and Langmuir models are applied to correlate the experimental data of humic substance and other model sorbents respectively. Multi component Adsorptive Model (MCAM) was used to simulate adsorption isotherms of model and natural sediment. The results reveal that(1) the separation efficiencies of carbonate, organic matter, ferric oxide, manganese oxide and alumina are 98.1%, 72.5%, 82.6%, 93.5% and 83.3%, respectively; (2) except for removing metallic oxide, the external structure of sediment is not changed greatly after separation; (3) the MCAM correlates the data of adsorption isotherm rather well with the maximal relative deviations of 9.76%, 6.78% and 9.53% for hexachloroethane, lindane and 1,2,4,5 tetrachlorobenaze in model sediment, respectively. The MCAM can clearly give expression to the different adsorptive mechanisms for HOCs in organic and inorganic matter, though the experimental data in each component are not very accurate due to the sequential separation efficiency.
文摘Hyperbranched polymer composed of G1 polyamidoamine (PAMAM) and branched with poly (propylene oxide) (PPO)-block-poly (ethylene oxide) (PEO) was investigated to interact with sodium dodecyl sulfate (SDS) and di-dodecyl dimethyl ammonium bromide (DDAB), respectively, by the methods of turbidity titration and analysis, rheology measurements, dynamic light scattering (DLS) and transmission electron microscopy (TEM). It was noticeable that even at extremely low concentration of SDS (even far from the critical micelle concentration (cmc)), the system exhibits high turbidity, indicating that SDS molecules can insert into cationic amine groups and hydrophobic microenvironment, resulting in the formation of polymer-SDS complexes with large size. At the SDS concentration range of below 0.1 mM, the turbidity and cloud point (CP) temperature of the system keep almost invariable, mostly because of the repulsion between SDS molecules and the complexes. And, therefore, the size of the mixed aggregates retains almost constant. In the case of vesicle system of DDAB, the aggregates are in the size of 100 nm - 200 nm and 500 nm - 3000 nm at the concentrations of 30 mM and 100 mM, respectively. However, in the mixture of hyperbranched polymer with DDAB, by comparison, the size is smaller in a binary system than that of in DDAB system. So it is reasonable to infer that DDAB molecules remove from multilamellar vesicles of DDAB to the hydrophobic microenvironment of hyperbranched polymer aggregates, with the addition of the hyperbranched polymer. It leads to the destruction of the gel-like conformation in DDAB system, leading to the shear thinning of the mixture and, as a result, the viscoelastic character of the system is lost in a large degree.
基金Project supported by the National Natural Science Foundation of China(Grant No.11164004)the Industrial Research Project of Guizhou Province,China(Grant No.GY[2012]3060)+1 种基金the Project of Education Department of Guizhou Province,China(Grant No.[2016]215)the Special Laboratory Fund of Education Department of Guizhou Province,China(Grant No.GY[2014]217)
文摘We have discussed the materials of solar cell based on hybrid organic–inorganic halide perovskites with formamidinium(NH_2CH = NH_2^+or FA) lead iodide. Firstly, we build the structure of formamidinium lead iodide(FAPbI_3) by using the material studio. By using the first-principles calculations, the energy band structure, density of states(DOS), and partial DOS(PDOS) of the hydrazine-iodide lead halide are obtained. Then, we theoretically analyze a design scheme for perovskite solar cell materials, published in [Science 354, 861(2016)], with the photoelectric conversion efficiency that can reach 20.3%. Also, we use non-toxic elements to replace lead in FAPbI_3 without affecting its photoelectric conversion efficiency. Here in this work, we explore the energy band structure, lattice constant, light absorption efficiency, etc. After the Ca, Zn, Ge Sr, Sn, and Ta atoms replacing lead(Pb) and through comparing the spectral distributions of the solar spectrum, it can be found that FAGeI_3, FASnI_3, and FAZnI_3 have better absorbance characteristics in the solar spectrum range. If the band gap structure is taken into account, FAGeI_3 will become an ideal material to replace FAPbI_3, although its performance is slightly lower than that of FAPbI_3. The toxicity of Pb is taken into account, and the Ge element can be used as a substitute element for Pb. Furthermore, we explore one of the perovskite materials, i.e., FA0.75Cs_(0.25)Sn_(0.25)Ge_(0.75)I_3 whose photovoltaic properties are close to those of FA_(0.75)Cs_(0.25)Sn_(0.5)Pb_(0.5)I_3, but the former does not contain toxic atoms.Our results pave the way for further investigating the applications of these materials in relevant technologies.
基金The work was supported by the National Natural Science Foundation of China.
文摘Organic matter and iron and maganese oxides have been considered as the major affecting factors for metals in anoxic or oxidized sediment. In recent research, clay and sulfide are found as major factors in oxic or oxidized sediments that might affect bioavailability of metals. To test this hypothesis, the influence of sulfide, measured as acid-volatile sulfide (AVS), and clay content on the bioavailability of zinc and cadmium in sediments was examined. Laboratory simulative experiment and field verification experiment were conducted, showing that the bioavailability of zinc and cadmium is strongly correlated to AVS and clay content in sediments. Taking into account both AVS and clay parameters in sediments together can better indicate the bioavailability of zinc and cadmium rather than considering one of them alone.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51761004,51661005,and 11964005)Industry and Education Combination Innovation Platform of Intelligent Manufacturing and Graduate Joint Training Base at Guizhou University(Grant No.2020520000-83-01-324061)+2 种基金the Guizhou Province Science and Technology Fund,China(Grant Nos.ZK[2021]051,[2017]5788,and J[2015]2050)High Level Creative Talent in Guizhou Education Department of Chinathe Cooperation Project of Science and Technology of Guizhou Province,China(Grant No.LH[2016]7430)。
文摘Two-phaseγ-TiAl/α_(2)-Ti_(3)Al lamellar intermetallics have attracted considerable attention because of their excellent strength and plasticity.However,the exact deformation mechanisms remain to be investigated.In this paper,a solidified lamellar Ti-Al alloy with lamellar orientation at 0°,17°,and 73°with respect to the loading direction was stretched by utilizing molecular dynamics(MD)simulations.The results show that the mechanical properties of the sample are considerably influenced by solidified defects and tensile directions.The structure deformation and fracture were primarily attributed to an intrinsic stacking fault(ISF)accompanied by the nucleated Shockley dislocation,and the adjacent extrinsic stacking fault(ESF)and ISF formed by solidification tend to form large HCP structures during the tensile process loading at 73°.Moreover,cleavage cracking easily occurs on theγ/α_(2)interface under tensile deformation.The fracture loading mechanism at 17°is grain boundary slide whereas,at 73°and 0°,the dislocation piles up to form a dislocation junction.
基金supported by the Chinese National Natural Science Foundation Grant 52074314
文摘An analytical solution in physical variable space is presented for transient gas flows during constant-rate production from a vertically-fractured well in an infinite homogeneous reservoir with finite fracture conductivity.The solution is based on the short-time asymptotic solution and a new approximate transient elliptical flow solution,which covers transient flows from the bilinear flow regime to the pseudo-radial flow regime.The solution covers the well-known asymptotic solutions in both short-and long-time limits of bilinear and pseudo-radial flows.The analytical model provides a practical and reliable engineering tool to evaluate the fractured reservoir properties,which can be programmed using a spreadsheet.
基金Hainan provincial natural science foundation (No.811213)
文摘Objective:To compare the efficacy and mechanism of zoledronic acid and Tc-MDP in the treatment of osteoporosis.Methods:From July 2011 to November 2015,232 patients with primary osteoporosis were selected and treated in The First Affiliated Hospital of Hainan Medical College were selected and were divided into the 116 patients in the Tc-MDP group and 116 patients in the zoledronic acid group accorded to the treatment ways.The zoledronic acid group were given zoledronic acid treatment,1 time in one year.The Tc-MDP group were given Tc-MDP treatment,and the treatment were treated for 10 days for 1 course,1 course for 3 months,and a total of 3 years of treatment were observed.The prognosis and the changes of bone mineral density and hematological parameters were recorded.Results:The total effective rates of the zoledronic acid group and Tc-MDP group were 99.1%and 90.0%,respectively,and the zoledronic acid group were significantly higher than the Tc-MDP group(P<0.05).The bone mineral density of lumbar vertebrae and hip after treatment were significantly higher than that of the two groups before treatment,and the zoledronic acid group were also significantly higher than the Tc-MDP group(P<0.05).The joint tenderness scores of the two groups were significantly lower than those before treatment,and the Tc-MDP group were also significantly lower than the zoledronic acid group(P<0.05).There were no significant differences in serum calcium and blood phosphorus levels compared between the two groups(P>0.05),and the erythroeyte sedimentation rate(ESR)levels were lower than before treatment(P<0.05),The ESR levels of the Tc-MDP group were also significantly lower than that of the zoledronic acid group(P<0.05).Conclusion:The zoledronic acid and the application of Tc-MDP in the treatment of osteoporosis can increase bone density,relieve joint tenderness symptoms,reduce ESR content,and will not affect patients'blood calcium and blood phosphorus levels.However,zoledronic acid increases bone density significantly are better than the Yunke,and Yunke relieves joint pain significantly are more than zoledronic acid.
文摘Objective:To observe the bone metabolism before and after131I treatment in premanopause female hyperthyroidism patients with low bone mass patients of different age.Methods:A total of 78 premanopause female patients hyperthyroidism with low bone mass were divided into two different age groups: premanopause female patients less than 35 years old in group A (n=38). Patients above 35 in group B (n = 40). 78 healthy adults of same age were enrolled as the control group. The bone mineral density (BMD) and bone turnover markers including type I procollagen N-terminal propeptide (PINP),β-C-terminal telopeptides of type 1 collagen (β-CTx) of two groups were measured before and 6 months and 12 months after 131I treatment to observe the bone metabolism and the restorablility of BMD.Results: After prolonged treatment with131I, PINP andβ-CTX of group A decreased and BMD increased gradually in a time-dependence way. And there was no significant difference when compared to the normal after 12 months. PINP andβ-CTX of group B decreased gradually, after 12 months, BMD of group B restored when compared to the level of before treatment but lower than group A.Conclusions: In young female hyperthyroidism patients with low bone mass (<35 years), BMD can be restored to normal levels as reversing of high bone turnover after131I treatment. Short-term clinical observation showed that high bone turnover was reduced partly in premanopause female patients (>35 years) treated only with131I , but still at a high level, BMD can not restored completely.